Alternating-current motor.



No. 347,153. PATBNTED MAR. 12, 1901.

. I BI J- ALTBRNATING GURRENT MOTOR.

,nrmonmn Hum 9110.19, 1903.

ZZZW

Ems-'5. J. Berg.

UNITED sir'Aegns PATENT OFFICE.

ERNST BERG, or SCHENEGTADL'NEW YORK, ASSIGNOR, TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK,

. AI TERNATING -V,GURRENT 'lvio-ron.

Specification of Letters Patent. Application filed December 19,1903. Serial No? 185,792.

Patented. March 12, 1907.

To all whom it may cancer/2;:

Be it known that I, ERNST J. BERG, a citizen of the United States, residing at Schenectady, county of Schenectady, State ofNew York, have invented certain new and useful Improvements in Alternating-Current Momotors o erated from three-phasecircuits,

connecte in delta. Across one side of said delta the supply-mains are connected, and across another side is connected a condenser. This connection gives good starting conditions, and I propose to employ a similar connection at starting; but I haye found that other connections and arrangement of apparatus give better runningconditions. My invention can best be described in connection with the annexed drawings, which is a rangeinent of one of its applications.

4 Referring to the drawing, A and B aremains connected with a single-phase source of supply, across which is connected the pri mary p of' transformer T. s and s are the secondaries of the transformer, and they have an equal number of turns, thus causingthe.

voltage induced in them by the primary to be equal. The ratio of turns in the secondarise to those of the primary can be made any that is: desired and so the voltage delivered by the secondaries can bemade to hear an desired relationto that of the source.

represents a motor havin the 'rotorR, which may be of. the equine c e or'any other Well-known t which is, continuous, out from it. Thus six sections a 12:0, 800., are

,formed, which taken inipairs constitute a.

three-phase winding or singly a six-phase It will be seen that the secondary .s of transformer T. is connected across the sections a and-b, which correspond toone side of the delta of a three-phase diagram illustrating the connections and ar' feature of my e, and a fiel -winding, ut has "six taps brought K is a quadrature device consisting of a condenser, which is connected through switch member m, across'sections e and f, which form a second side of a three-phase delta.

Thus if transformer secondary s is energized and condenser K is connected, as shown, the motor has precisely the .arrangement of the Steinmetz motors abo referred to and good .starting torque is obtained.

In order to secure greater torque and efficiency under running conditions, the transformer secondary s is connected to tap's- 4.

and 6 across sections d and e. Thus two parts of the winding one hundred and eighty electrical degrees apart are energized by the two transformer secondaries s and s. The relative directions of the currents in the two parts at any moment are indicated by-the arrows, it being understood that the direction of both'arrows is periodically reversedj,

By thus directly energizing these two parts of the winding practically all thewinding is made efiicient in producing a useful torque. The sections 0 and f, position could exert little useful torque, are not connected in circuit, and consequently any voltage drop through these' parts is avoided.

z, Although the connection of thecondenser .as shown in the drawingis suitable for producing a good starting torque, I have discovered that the power factor and efficiency of the motor may be increased under running conditions if the condenser 1s connects across a art of the winding HiSJlBIiE-d ninety,

degrees instead of one hundre and twenty degrees from the magnetizingswinding. One invention consists in shifting the connection of one terminal 01 the condenser from tapl to tap 2 thereby including section a in addition to sections e and f, thus placing the condenser across a part of the winding displaced ninety electrical 'de ees.

irom the ma eti'zingl-f'vtvind' s-a b an d e. To accomplis this s connections is the purpose 'of switch member m and a regulatin -resistance 1'. Switch member m'is arrange to engage switch-conwhich because of their ing 0 the condenser tacts to which resistance r is connected; As

the motor-speeds up and as switch member m is moved from ri ht to left parts of resistance r are pro ressive y placed in series with condenser Kj thereby gradually -decreasing the -.condensercurrent. When switch member may beapplied to a motor having any number of poles and any well-known form of V winding.

Accordingly I do not desire to limit myself to the particular construction and ar-.

rangement of parts here shown, since changes therein which do not depart irom the spirit of my invention and which arewithin the scope of the appended claims will be ob'viou to those skilled in the art.

What I claim as new, and desire to secure by Letters Patent of the United States, is-

-1. In combination, an induction-motor having a continuous windin", a source of 'current connected to a part oi said winding, a condenser connected in a certain relation to said winding at starting, and means for shifting the connections of said condenserto a part of said winding displaced ninetyeled trical degrees from the part ofsaid winding 'connected to said source.

2. 'In combination, an induction-motor having a continuous winding, 'a source of current connected across one-third of said wind ng, a condenser connectedjacross an adjacent third, and means for sln'ft'ing the con nect ions'of' said condenser to include halfof the first-named third.

3. In combination, an induction-motor having a three-phase wmding, a source of current connected to one phase ofsaid winding, acondenser and means for connecting said condenser to a second phase ofsaid wmdmg and for then slnftm the connection of one terminal of said condenser from the endv to the middle of the first-named phase.

4. In combination, an induction motor having a continuous winding, independent sources of current connected to energize two parts'of said-winding displaced from each other, one hundred and eighty electrical 'degrees, a condenser, and means'for connectin said condenser-to the-middle of one of sai parts'and to the end of the other of said parts, and then connecting said condenser to the middle of both parts.

5. In combination, an

induction} motor having a continuous winding, a. single' pihasesource OfSHPJfl-Y, two independent 's'upply-cir cu'its derive therefrom and connectedi-e-. .spectively to .two parts of said placed from each other one himdred and eighty electrical degrees, a condenser, and

means for connecting said condenser variably to said windings.

'6. In comblnation, an induction-motor, a

single-phase source of supply, sup ly-circuits derived therefrom and connecte to the wmdmgs of said motor, a phase-advancing device connected in acertam 16l2tl/10I1 t0 said windings at starting, and means for changing the connections of said device 'to said wmdings when the motor is running.

7. In combination, an induction-motor having a winding in six sections connected to form a continuous winding, two independent supply-circuits each connected to a pair of .adjacent sections and said pairs bein d is' .placed from each other one hundrec and eighty electrical degrees, a condenser having one terminal connected to the middle point of one of said pairs, and means for variably connecting the other condenser-terminal to the end or to the middle point of the second 4 of-said pairs.

8. In combination, an induction-motor, a condenser having one terminal permanently connected to a point on the winding of said motor,-means for connecting the other terminal of the condenser to one point on said winding when said motor is. starting and to another point when said motor is running, and means for insertln a resistance 1n series with said condenser w en changing the connection of said terminal.

9. In combination, an induction-moton'a single-phase source of supply, independent. supply-circuits derived therefrom and) connected to the windings of said motor a condenser, and means for variably connecting said condenser to the windings of said motor.

10. The combination with an alternatingcurrent machine, and a single-phase circuit connected therewith, of a quadrature device connected with the primary element of the machine, theconnections thereofbeing at an angle to those of the single-phase circult, and

means for shifting the connections of the" quadrature device. I

- 11. The combination with an alternatmgcurrent'machine, and a single-phase circuit connected therewith,- offia condenser con- =-nected with the primaryelementof the ma chine, and means for shifting the connections ofthecondenser relative to the connections of'the single-phasecircuit.

12. The combination with an alternating-- current machine, and a single-phase circu t connected therewith, of a quadrature device connected with the primary element ofithe machine, and means for the connec= tions of thequadrature device relative to the. connections of the single-phase circuit.-

13. The combination withan alternatingcurrent machine, and a singlephese circuit connected therewith, of a quadrature device connected With the primary element of the uadrature device, and means for regulating t 1e current taken by the quadrature device.

14. The combination with an alternatingcurrent machine, and a single-phase circuit connected therewith, of a quadrature device connected with the mimary element of the machine, means for shiftiin the connections of the quadrature device re ativc to the connections of the. single-phase circuit, and nic ans for regulating the current taken by the quadrature device.

a 15. The combination with an alternatingcurrcnt machine, and a singlephasc circuit connect-ed therewith, of a condenser connected with the primary element of the machine, the connections thereof being at an angle to those of the single-phase circuit, and means for shifting the connections of the condenser.

16. The combination with an alternatingcurrent machine, and a single-phase circuit connected therewith, of a condenser connected with the primary. element of the maehine,.the connections thereof being at an angle to those of the single-phase circuit, means for shifting the connections of the 0on denser, and means for regulating the-current taken by the condenser.

. 17. The combination with an alternatingcurrent machine, and a single-phase circuit connected therewith, of a condenser connected with the primary element ofthe machine, means for shifting the connections of the condenser relative to the connections of the single-phase circuit, and means for regulating thecurrent taken by the condenser.

'In witness 'whereof I have hereunto set my hand this 17th day of December, 1903.

- ERNST J. BERG. Witnesses:

BENJAMIN B. HULL, HELEN ORFORD. 

